<div dir="ltr"><font color="#003333"><font size="2"><font face="trebuchet ms,sans-serif">I would appreciate some advice about the best way to manipulate data structures in Haskell.</font></font></font><div><font color="#003333"><font size="2"><font face="trebuchet ms,sans-serif"><br>

</font></font></font></div><div><font color="#003333"><font size="2"><font face="trebuchet ms,sans-serif">Let&#39;s assume I have what in an OO language would be a class with a number of instance variables. When I want to change one of the values of one of those instance variables in Haskell I must rebuild the entire structure. Even worse, if one of those instance variables is a reference to another data structure, then when I change that referenced data structure, I am forced to rebuild my top level variable. For example.</font></font></font></div>